Toronto, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.4 °C (low) to 11.3 °C (high). Annual precipitation averages 696.5 Millimeters. Toronto is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.2 °C | -6.3 °C | 17.02 mm |
| February | -13.8 °C | -3.8 °C | 16.76 mm |
| March | -7.2 °C | 3.1 °C | 35.05 mm |
| April | -0.3 °C | 11.4 °C | 66.29 mm |
| May | 6.9 °C | 18.7 °C | 91.95 mm |
| June | 12.7 °C | 23.9 °C | 116.08 mm |
| July | 15.3 °C | 26.9 °C | 88.9 mm |
| August | 14.2 °C | 25.8 °C | 81.28 mm |
| September | 9.4 °C | 21.5 °C | 78.49 mm |
| October | 1.7 °C | 13.6 °C | 56.13 mm |
| November | -5.8 °C | 4.3 °C | 27.18 mm |
| December | -12.6 °C | -3.4 °C | 21.34 mm |
| Annual | 0.4 °C | 11.3 °C | 696.47 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |